Method of rolling hexagon bars



Patented Jan. 8, 1935 PATENT OFFICE 1,987,324 METHOD or ROLLING HEXAGONBARS William .11". Catterall and William I. am, manon,-Pa., assignors toBethlehem Steel Company, a corporation of Pennsylvania ApplicationDecember 6, 1932, Serial No. 845,890.

70lalms.- (01. 80-6 3) This invention relates to improvements in themethod of rolling symmetrical polygonal bars and particularly to hexagonbars.

The objects sought to be attained are: first,

.5 such accuracy in size and shape of the finished bar as to permit themaking of hexagon nuts from the bar without the usual additionaloperation of cold rolling or drawing the barto obtain this accuracy insize and shape; second, to provide suitable form of bars forautomatically repeating from one pass to the next on continuous ormechanically-fed mills.

In the manufacture of certain kinds of nuts it is the usual practice totake an ordinary hot rolled hexagon bar and cold roll or draw the bar toobtain the size and shape as required by trade specifications. Thisnecessarily adds to the cost of the finished article, not only from theextra labor and time consumed but also from the additional equipmentnecessary for these operations.

By our improved method of rolling we eliminate the cold rolling ordrawing operation by producing a bar having shape and sizecharacteristics equivalent to a cold rolled or drawn bar of the samesize which is acceptable to the trade.

In the previous method of rolling hexagons, the finished bar was usuallyrolled from an oval in five to seven passes. The shapes following theoval were preferably squares, diamonds and other configurations whichresulted in accumulating inaccuracies and distortions to the extent thatthe finished product had to be cold rolled or drawn to bring the rolledbar to accurate size and shape for the manufacture of certain kinds ofnuts which are extensively used.

The novel features will be more fully understood from the followingdescription and claims taken with the drawing.

' Fig. 1 represents a round billet bar.

Fig. 2 represents a roll pass and a section of the leader formed fromthe round bar of Fig. 1.

Fig. 3 represents the finishing roll pass and the section of the hexagonbar formed from the leader of Fig. 2.

In rolling symmetrical polygonal sections it is advantageous to get asection as near to the finishing pass as practicable, over which theroller has as much control of the exact shape and sectional area aspossible. This is the round, which has but one sectional dimension. Theroller can get this round. as accurate to size as a finished round, andin the two remaining passes, the billet being turned 90 for the lastpass, any slight inaccuracy of the round is diminished so that it ispossible to work to even closer accuracy in making hexagons this waythan the accuracy of rounds rolled in the usual manner.

1 In Patent 706,994 to Nighman there is disclosed a method of rollingpolygonal sections using an .oval from which the leader is formed.However, 5

no great accuracy can be obtained by this method, as the oval to startwith has two dimensions against one for the round, and the oval is moredifiicult to roll true to shape than. a round. Again-an oval must beturned for the succeeding 10 pass, whereas a round does not need to beturned with the resulting inaccuracies on entering the second pass.Therefore in forming the leader we start from a round, which produces aleader of greater uniformity than that produced by an oval or any othershape known to us. The novelty of this invention comprises the rollingof the finished hexagon bar from the shape of Fig. 1 with but oneintermediate pass.

In the first pass, the round is reduced to the shape as shown in 2. Thisshape has two pairs of fiat sides 10 which converge to points 11 and 12,the bases of the fiat sides being connected by concave surfaces 13. Thisshape is called the leader. .The leader before entering the finishing 25pass Fig. 3 is turned at right angle so that the finishing pass tends tocompress and spread the pointed ends of the leader which increases theangularity of said ends so as to fill out the concave portions of theleader without forming fins 30 at the parting of the rolls. The width ofthe fiats of the leader being substantially the same width of thefinished faces 14 of the hexagon. By this method, having started with anaccurately formed round, we are able to roll .a leader partly of the 3final shape which has consistent accuracy of shape and section and withthis accurately formed leader we are able to produce a hexagon havinggreater accuracy of shape and section than any hot rolled bar heretoforeproduced. In the final shape the faces will all be the same length andhave the same angular relation one to the other.

The tolerance practice as specified by the Association of American SteelManufacturers is .020" for to 1" hexagons, and .046" for 1" to 2"hexagons. By our method of rolling we roll bars to a tolerance as low'as.006" on all sizes.

Although we have particularly described the rolling of a hexagon, it isto be understood that our method is also applicable to other polygonalshapes. The only difierence being in selecting a suitably shaped leaderfor the final shape. The round still being used to form the leader inorder to obtain accuracy. Any suitable type of.

continuous, mechanically-fed mill or hand-fed mill may be employed forcarrying out our improved method of rolling.

' By this our improved method of rolling we 5 are enabled to roll a barhaving tolerances and shape equivalent to a cold rolled or drawn barwhich we believe has not heretofore been accomplished, thereby making avery substantial saving in cost of productionnotonly in time and laborbut in the elimination of cost and of cold rolling or drawing apparatus.

Having thus described our invention, what we claim as new and desire tosecure by Letters Pat-j ent, is:

1. In the manufacture of hot rolling hexagon bars having shape andtolerance characteristics equivalent to a similar cold rolled or drawnbar, the steps comprising forming a leader having a major axis and aminor axis from a substantially circular cross section bar, supplyingthe leader to a rolling mill in such a manner that the direction ofcompression of the leader in the mill is along the long cross sectionaldimension of the leader, and rolling the leader to a finished hexagon.

2. In the manufacture of hot rolling hexagon bars having shape andtolerance characteristics equivalent to a similar cold rolled or drawnbar, the steps forming a bar having but one cross sectional dimension,rolling said bar to form a leader of elongated section having pointedends and concave side portions, and finish rolling said leader in ahexagon pass to compress and spread said pointed ends and fill out theconcave side portion of the leader so as to form a substantially perfecthexagon having said characteristics.

3. A method of rolling hexagons including the producing of a round oflarger section than the 40 finished hexagon, rolling in one pass saidround to a leader having fiat pointed ends and two oppositely disposedconcave sides forming major and minor axes respectively, the width ofthe leader across its major axis being greater than 4 the diameter ofsaid round and the depth through its minor axis being less than saiddiameter, and reducing said leader to a hexagon in another pass.

4. A method of hot rolling hexagon bars of ac- 50 curate section,including the continuous feeding of a heated round bar of greaterdiameter than the finished section to a rolling mill leader pass adaptedto reduce the top and bottom convex surfaces of said round to oppositelydisposed 55 concave surfaces and to spread the side portions of theround to form oppositely disposed pointed upkeep portions, turning thesection thus formed 90, and in another pass continuously reducing saidsection to a hexagon.

5. A method of rolling accurately shaped hexaand in a single hexagonpass compressing said:

leader in the direction of its major axis to reduce its major dimensionand simultaneously a increase the angularity between the flattened endsand widen the section in the direction of its minor axis thustransforming said concaved faces to straight parallel faces of equallength of the finished angular end portions, whereby to produce a truehexagon having corners equally spaced circumferentially and radially.

6. A method of rolling accurately formed hexagon bars including theproduction of a substantially round bar of larger section than thefinished hexagon, compressing said roundinarollpasspartlyofthefinalshapesoasto effect a reduction of the roundin one direction and uniformly spread the same ina direction opposite tothat of the compressive force of the rolls to form an undistorted leaderhaving opposed angular ends and opposed concaved sides allcorrespondingly equal in length and symmetrically disposed relative toits axes, and reducing said leader to a hexagon having faces of equallength forming corners equally spaced circumferentially in another rollpass.

7. A method of rolling accurately shaped hexagons, including theproducing of a round of larger section than the finished hexagon,deforming said round in a roll pass to a symmetrically shaped leaderhaving pointed ends forming fiat faces of lengths substantially equal tothe finished hexagon and concaved side faces of greater length than thefaces of said hexagon, feeding said leader to a true hexagon roll passso as to compress said leader section in the direction of its pointedends to spread said pointed ends and simultaneously laterally spreadsaid concaved faces in one direction while shortening their length in anopposite direction, whereby to completely fill out the pass withoutfinning at the parting of the rolls.

WILLIAM H. CA'I'IERALL. WlILIAM J. BARRY.

CERTIFICATE oE' CoRRECTIoNL' Patent No. 1,987,324. January s, 1935.

WILLIAM H. CATTERALL, ET AL.

It is hereby certified that error appears'in the printed specificationof the;

aiiovenumbered patent requiring'correction as follows: Page 2, firstcolumn,

line 29, claim 2, after "steps" insert the word comprising; and that thesaid Letters Patent should'be read with this correction therein that,the same may conform to the record of the case in thePatent Office.

Signed and sealed this 11th day of June, A. D. 1935.

Les] ie Frazer (Seal) Acting Commissioner oi Patents

